Polymer biodegradable medical device

Abstract

A medical device that is at least partially formed of a biodegradable polymer. The medical device can be at least partially formed by MEMS technology. The medical device can include one or more micro-structures that are also formed by MEMS technology. The medical device can include one or more biological agents that can be controllably and/or uncontrollably released from the medical device,

We claim: 
     
       1. A method of reducing stent strut fracture problems that can result from repeated bending of said stent in a body passageway comprising:
 a. selecting a stent having a body portion, said body portion having an unexpanded and expanded cross-section area, a majority of said body portion at least partially formed of biodegradable polymer so as degrade over time when exposed to fluids in the body passageway to thereby remove itself from a treatment site in said body passageway, said body portion includes at least one cavity, said cavity at least partially filled with a biological agent; 
 b. positioning said stent at said treatment site of said body passageway; 
 c. expanding said body portion of said stent in said body passageway to said expanded cross-sectional area; and, 
 d. allowing said body portion of said stent to flex in said body passageway such that continual flexing of said body portion results in at least one fracture in said body portion, said fracturing of said body portion resulting in accelerated degradation of said body portion at the site of said fracture thereby causing accelerated absorption of said body portion in said body passageway. 
 
     
     
       2. The method as defined in  claim 1 , wherein said biodegradable polymer is at least partially coated with a non-biodegradable polymer. 
     
     
       3. The method as defined in  claim 1 , wherein an outer surface of said body portion includes a plurality of said micro-structures, said plurality of said micro-structures extending outwardly from said outer surface of said body portion, said plurality of said micro-structures including biodegradable polymer, biological agent, or combinations thereof. 
     
     
       4. The method as defined in  claim 3 , wherein said plurality of said micro-structures include said biological agent, said plurality of said micro-structures designed to at least partially penetrate into or depress on an inner surface of a body passageway when said body portion is expanded to said expanded cross-sectional area at said treatment site of said body passageway so as to result in local delivery said biological agent into a wall of said body passageway, on a localized region on a wall of said body passageway, or combinations thereof. 
     
     
       5. The method as defined in  claim 4 , wherein said plurality of said micro-structures include a cavity at least partially formed by said biodegradable polymer, said cavity at least partially filled with said biological agent. 
     
     
       6. The method as defined in  claim 5 , wherein said cavity in said body portion is connected to said cavity in said plurality of said micro-structures. 
     
     
       7. The method as defined in  claim 6 , wherein said body portion includes biological agent on said outer surface of said body portion, said biological agent on said outer surface different from said biological agent in said cavity. 
     
     
       8. The method as defined in  claim 7 , wherein said biological agent on said outer surface of said body portion, in said cavity or combinations thereof is formulated to at least partially inhibit re-narrowing of the vessel diameter, inhibit thrombosis, facilitate endothelium generation, create an integral endothelial layer, or combinations thereof. 
     
     
       9. The method as defined in  claim 5 , wherein polymer coats a portion of said plurality of said micro-structures to encapsulate said biological agent in said cavity of said plurality of said micro-structures, said polymer including a biodegradable polymer, a biostable polymer, or combinations thereof. 
     
     
       10. The method as defined in  claim 3 , wherein plurality of said micro-structures include biological agent, said biological agent includes one or more agents selected from the group consisting of trapidil, trapidil derivatives, taxol, taxol derivatives, cytochalasin, cytochalasin derivatives, paclitaxel, paclitaxel derivatives, rapamycin, rapamycin derivatives, GM-CSF and GM-CSF derivatives. 
     
     
       11. The method as defined in  claim 3 , wherein said biodegradable polymer includes one or more polymers selected from the group consisting of chitosan, a chitosan derivative, PLGA, a PLGA derivative, PLA, a PLA derivative, PEVA, a PEVA derivative, PBMA, a PBMA derivative, POE, a POE derivative, PGA, a PGA derivative, PLLA, a PLLA derivative, PAA, a PAA derivative, PEG and a PEG derivative , or combinations thereof. 
     
     
       12. The method as defined in  claim 3 , wherein said body portion includes a radiopaque marker material, said radiopaque marker distributed throughout said body portion of said stent, or a certain location on said body portion of said stent. 
     
     
       13. The method as defined in  claim 3 , wherein said biological agent imparted to said body portion of said stent by spray coating, dip coating, roll coating, sonication, brushing, plasma deposition, depositing by vapor deposition, or combinations thereof. 
     
     
       14. The method as defined in  claim 1 , wherein said biological agent includes one or more agents selected from the group consisting of trapidil, trapidil derivatives, taxol, taxol derivatives, cytochalasin, cytochalasin derivatives, paclitaxel, paclitaxel derivatives, rapamycin, rapamycin derivatives, GM-CSF and GM-CSF derivatives. 
     
     
       15. The method as defined in  claim 14 , wherein said biodegradable polymer includes one or more polymers selected from the group consisting of chitosan, a chitosan derivative, PLGA, a PLGA derivative, PLA, a PLA derivative, PEVA, a PEVA derivative, PBMA, a PBMA derivative, POE, a POE derivative, PGA, a PGA derivative, PLLA, a PLLA derivative, PAA, a PAA derivative, PEG, and a PEG derivative. 
     
     
       16. The method as defined in  claim 15 , wherein at least one polymer coats a portion of a plurality of said micro-structures to cause said biological agent in said cavity of said plurality of micro-structures to be encapsulated in said cavity, said at least one polymer including a biodegradable polymer, a biostable polymer, or combinations thereof. 
     
     
       17. The method as defined in  claim 16 , wherein said outer portion of said body portion includes said biological agent, said biological agent on said outer surface different from said biological agent in said cavity of said plurality of micro-structures.